Pump



A. J. sYRoV-Y Sept. 13. 1938.

PUMP

Filed July 5, 1935 2 shuts-sheet 1 In @A .m Q d I w Sept. 13, 1938.

A. J. SYROVY PUMP Filed July 5, 1935 2 Sheets-Sheet 2 I\NVENTOR.flzzyzzsiz'zz J7 Syra r BY ATTO 151 5 Patented Sept. 13, 1938 UNlTEDSTATES PUMP Augustin .l. Syrovy', Detroit, Mich, 'assignor to ChryslerCorporation, Highland Park, Mich., a

corporation of Delaware Application July 5, 1935, Serial No. 29,788

1 Claim.

This invention relates to pumps and refers more particularly toimprovements in pumps adapted to produce and maintain pressure on afluid, such as oil, suitable for use in systems of a motor vehicletransmission control although my improvements are adaptable to a widevariety of applications. Asillustrative of one system of transmissioncontrol to which my pump is adaptable, reference is made to theco-pending applilil cations Serial No. 724,434 filed May 7, 1934 andSerial No. 752,948 filed November 14, 1934.

One object of my invention is to provide an improved pump which willefiiciently and quickly m provide a relatively high pressure of the oil,such pressure is attained.

Further objects of my invention are to provide a pump having improvedcharacteristics of fiuid seal; a pump capable of long and continuousservice such as is required in motor vehicle usage, without undue heatgeneration, noise, wear or failure through other causes.

Another object of my invention is to provide an improved pump havingrelatively rotating parts for self adjustment whereby wear is minimized,fluid seal is promoted, and manufacture and assembly of the pump partsis facilitated.

A further object of my invention is to provide an improved control ofthe pressure of the fluid developed by the pump; minimize noise incidentto operation of the pump and particularly during the porting events inthe cycle of pumping operation; and to provide a compact and novelarrangement of pressure accumulator and control of pressure delivery.

In carrying out the objects of my invention, I preferably employ a pumpof the wabble plate type adapted to vary its inclination or level-off inresponse to fluid pressure delivery to automatically maintain apredetermined delivery pressure; also to minimize movement of the pumpparts after the iluid has reached its predetermined desired pressure. Asa feature of my invention the pump is arranged for maximum delivery toquickly build up its desired pressure, the fluid displacement by thepump then Ming quickly reduced. instead of being gradually reduced as 5Dthe pressure builds up to the desired maximum.

Further objects and advantages of my invenreside in the novelcombination and arrange-- ment of. parts more particularly hereinafterdescribed and claimed, reference being had to the 55 accompanyingdrawings illustrating several empressure being maintained preferablywithout requiring operation of the pump after the required (Cl. Nit-4W2)bodiments of certain features of my invention and in which:

Fig. 1 is a sectional plan view of my pump assembly taken along line |-lof Fig. 2.

Fig. 2 is a side elevational view of the pump assembly, with certainparts in cross section.

Fig. 3 is a sectional view along line33 of Fig. 1.

Fig. 4 is aside elevational view of the right hand end of the pumpviewed in Fig. 1.

Fig. 5 is a detail sectional view along line 5-5 of Fig. 1.

Fig. 6 is a detail sectional view along line '6--6 of Fig. 5.

Fig. 7 is a fragmentary View of a-pump rotor and port seating element ofmodified form but adapted for use in the Fig. 1 assembly.

Fig. 8 is a detail sectional view along line 8-8 of Fig. '7.

Referring to the drawings the pump assembly comprises a casing structureA adapted for attachment at openings in to a suitable support such asthe transmission structure of a motor vehicle (not shown). The casingreceives the pump drive shaft I l journalled at one end in a bearing l2carried by the casing and supported at the other end in a cylindricalported base portion l3 of the casing in a manner moreparticularlyhereinafter set forth.

The shaft H has a drive gear I l suitably fixed thereto and adapted toreceive power from a suit: able source such as a drive shaft of thetransmission (not shown); Base 13 has inlet and outlet passages l5 andi6 respectively for the fluid, such as oil, admitted to the pump anddelivered therefrom under pressure. The inlet i5 is exposed to asuitable reservoir of oil which has a level above this passage or insuitable communication with a reservoir of oil as may be desired.

Tightly pressed into the cylindrical opening ll of base 93 is acylindrical port seat body or ring it formed of bronze or other suitablematerial journalling the adjacent end of shaft 5 I, this body havinginlet and outlet passages l9 and 20 communicating radially at one endwith passages l5 and it respectively. The other ends of the passages land 20 form circumferentially spaced arcuate inlet and outlet ports 2iand 22 having their adjacent ends terminating in relatively narrow pairsof grooves 23, 24 and 23 24 The grooves. of each pair taper toward eachother (see Fig. 6) and are brought closely together preferablysumciently so that they are momentarily brought into communication witheach other by the inlet and outlet ports of the pumping cylinders aswill presently be apparent.

Surrounding shaft II for rotation therewith is the pump rotor Bpreferably of steel or other suitable material. This body is keyed orotherwise fixed at 25 to shaft II and preferably has a. clearance withthe shaft sufl'lcientto permit the body to slightly shift its positionso that the surface at the cylinder head end 26, which is rotatablyslidably engaged with the adjacent ported surface of body l8, mayaccommodate itself to the latter surface. More specifically, in the formillustrated, the body B has a generally cylindrical opening 21accommodating the shaft II, this opening tapering from the keyed end ofbody B, which fits the shaft, to the opposite end. The body B may thusrock 'about its inner end at key 25 for relatively free movement at thesurface of ports 2i, 22 whereby the bodies l8 and B are relativelyself-adjustable to provide and maintain a good fit preventing leakage,wear, and binding of the parts. Furthermore, when the pump is run-in, aself-lapping action takes place at the rubbing surfaces between bodiesi8 and B. The body B has a plurality of circumferentially spacedcylinders 28 opening inwardly toward a wabble or swash plate C, thecylinder head portion 26 having ports 29 for each cylinder. These ports,as body B rotates, successively register with ports 2| and 22 so thatthey are alternately intake and discharge ports.

Each cylinder 28 slidably receives a piston 30 urged inwardly by aspring 3| into contact with plate C, the inner rounded end 32 of eachpiston slidably engaging the outer ring 33 of the plate C. This ring issupported by bearing 34 carried by a swinging arm 35 pivotally supportedat 36 from casing A. At the other side of shaft II the arm 35 ispivotally connected at 31 to an outwardly extending link 38 pivoted at39 to a lever 40. The lever is pivotally supported at 4! to a projection42 of the outer'closed end of the accumulator cylinder D.

Slidable in cylinder D is a piston 43 urged inwardly by a heavy spring44, the piston having an outwardly extending rod 45 adapted to engagelever 40 to swing the latter to the dotted position in Fig. l forlevelling-off the plate C and minimizing or eliminating reciprocation ofpistons 30. Piston 43 moves against spring 44 in response to apredetermined desired pressure of'the fluid delivered by the pump, thedelivery passage 20 being in communication through passage 48 with, theaccumulator cylinder D at the discharge 41. The oil under pressure isled to a suitable point of usage from cylinder D through the casingpassage 48. A cover plate 49 is -secured by fasteners II to the innerend of the casing A and closes oi! the inner end of cylinder D and thechamber of auxiliary pump E where such pump is employed. 7

The pump E comprises a driving gear II and driven gear 52 together withoil inlet and outlets 53, respectively, and is-adapted to supply oilunder a relatively low pressure to lubricate parts of the engine ortransmission (not shown).

As the shaft l I drives rotor B, with plate C positioned asin Fig. 1 formaximum piston stroke.

approximately half of pistons 20 are moving inwardly drawing in oilthro'ugh port 2| and ports 29 associated therewith, while the remainingpis tons are discharging oil under pressure through their associatedports 28 andoutlet port 22 for passage to cylinder D at 41. As eachvport 20 moves across the face of body ll between ports 22 and 2i thereofto cut-oflpressure deliveryand piston moves to the outward limit of itstravel is not abruptly cut-off but such action takes place verygradually as the port 28 progressively moves to include groove 24. Sincegroove 24' narrows toward groove 22, the cut-off is further accentuatedin a gradual manner, the port 28 momentarily registering with groove23'- just prior to passage beyo'nd groove 24'. In this manner I havefound that a very quiet and efllcient pumping action is obtained, freefrom hydraulic "hammer and other noises incident to pumping. In passingfrom intake to pressure delivery between parts 2 i and 22, I preferablyprovide similar grooves 22, 24 for a similar action with each cylinderport 29 as will be readily understood.

When the pump is initially operated, the pressure of the oil deliveredat 41 to cylinder D rapidly builds up to the desired amount, say 500pounds per square inch for example, and as this pressure is nearlyreached (determined by the value of spring 44) the piston 43 movesoutwardly increasing the capacity of cylinder D and moving rod 45 intocontact with lever 40. Continued movement swings lever 40 and therebyswings plate C about its pivot 36 into a position approximatelytransverse to the axis of shaft l I. This levelling-oi! of plate Cprogressively lessens the stroke of pistons 20 until they finally aresubstantially motionless so far as reciprocation is concerned, assumingof course that oil under pressure is not being relieved from thedelivery system. Any minor leakages which may be present in the deliverysystem will require only a small movement of the pistons to maintain themaximum desired oil pressure in the cylinder D.

By normally spacing rod 45 from lever 40, there is provided a lostmotion connection between the wabble plate structure and the controltherefor and the plate C does not start to level-off as soon as piston43 begins to move accompanied by further compression of spring 44 sothat the maximum stroke of the pistons 22 is realized longer thanotherwise. In this manner the maximum.

pump pressure is rapidly attained. The plate C is, of course, free toassume any position intermediate its inclined position of Fig. 1 and itsfully levelled-oi! position under control of rod 45 according to thedemand placed on the delivery system. It will therefore be understoodthat while the wabble plate C is normally swingable about its pivotalmounting in response to actuation of the control therefor, including therod 45, this plate is free from such movement and is not actuated whenthe control member is operated in opposite directions respectively bythe fluid pressure within the cylinder D and the spring 44 in taking upand establishingthe lost motion connection between the plate 40 and thecontrol therefor.

It should be noted that, in levelling-off, the plate 0 moves the pistons2| outwardly to the outer limit of their travel. This is desirable inminimizing air trapping between cylinder head 20 and'the outer ends ofcylinders 28.

The accumulator cylinder D stores oil under 1 pressure so that when oilis delivered under preslater spring 44 also asthe load medium control-'76 aiaaeso ling the regulation of the stroke oi pistons 3| andconsequently controlling regulation of the pump delivery.

Referring now to the modified form of my m vention shown in Fig. 7, Ihave illustrated only a portion of the pump assembly of Fig. 1,iii/being understood that my Fig. 7- structure may be readily used withthe Fig. 1 assembly as will be readily understood. Similar parts aredesignated. by similar reference characters.

' In Fig. 7 the body 8' does not have a clearance with shaft H, therelative self-adjusting movement between the face of cylinder head 26'having ports 20' and the face of the non-rotating member 55 having inletand outlet ports 2i,'22 resulting in a self-lapping and sealing actionas aforesaid. Thus, the casing part if tightly receives the cylindricalbody I! formed with intake and delivery passages 19' and 20 but theadjustable member 55 is now interposed between bodies I. and B.

The member 55 is formed with a spherical convex outer face 56 fltting alike concave spherical face of body I! so that relative adjustment mayreadily take place between the relatively rotating faces of body B andmember I5. In order to permit the desired small amount of relativemovement between body it and member 55 and at the same time to preventmember 65 from rotating with body B, a pin 51 is passed through body IIand enters member I! (circumferentially spaced from passages l9 and 20')in an opening 58 thereof having a clearance with pin 51.

Ina fluid pump, a supporting structure, a drive ,,shaft Journaled insaid supporting structure, a

direction of said shaft, a wabble plate control piston in said cylinder,means for conducting fluid under pressure from said fluid conductingmeans to said cylinder for operating said control piston, a spring,acting to oppose movement, of said control piston by said fluidpressure, a rod secured at one end thereof to said piston and extendingthrough said spring, a lever supported for pivotal movement and lyingbeyond but in the path of movement of the other end of said rod andconstituting a lost motion connection between said control piston andsaid wabble plate, and a link connecting said lever and wabble plate forswinging said wabble plate in response ,to

movement by said control piston, said lost mo-" tion connectionaccommodating substantial fluid pressure movement ofsaid piston prior toswinging movementof said wabble plate in responseto fluid pressure insaid cylinder.

, a AUGUSTIN J. SYROVY.

What 1,018.!!! is:

